Rosemary oil for hair growth: what the study found and how to use it

Rosemary oil for hair growth went viral on the strength of one study: a 2015 trial in which rosemary oil performed about as well as 2% minoxidil over six months. That result is real, but it was small and has not been widely repeated, and rosemary oil is not a proven treatment for hair loss. If you want to try it, dilute it properly, give it at least six months, and see a doctor if your hair loss is sudden or patchy. Here is what the research shows and how to use it safely.

General information, not medical advice. See a dermatologist to find the cause of hair loss before treating it.

What the study found

In a randomized trial published in Skinmed, 100 people with androgenetic alopecia (pattern hair loss) used either rosemary oil or 2% minoxidil for six months. Neither group saw a significant change in hair count at three months. By six months, both groups had a significant increase in hair count, with no significant difference between them. Scalp itching increased in both groups, but was more common with minoxidil.

The limits of that evidence

• One small trial: 100 participants, and it has not been confirmed by larger studies.
• A weak comparison: it compared rosemary with 2% minoxidil, a lower strength than the 5% often used today; see minoxidil for women.
• The study group: participants had pattern hair loss, so the results do not apply to shedding after illness, stress, childbirth or low iron.
• Product differences: the oil used in a study is not the same as every bottle sold online.

Rosemary oil vs minoxidil

How to use rosemary oil on your scalp

1. Always dilute it. Undiluted essential oil can irritate or burn the skin. A common approach is a few drops of rosemary essential oil in a tablespoon of a carrier oil such as jojoba.
2. Patch test on your inner arm for a day or two.
3. Apply to the scalp, not the lengths, parting your hair in sections.
4. Massage gently for a few minutes.
5. Leave it on for a few hours or overnight, then shampoo, twice if needed.
6. Repeat a few times a week and give it at least six months.

Some people prefer ready-made rosemary scalp serums, which are already diluted and lighter to wash out.

Does rosemary water work?

Rosemary water, made by simmering sprigs in water, is popular as a lighter alternative. There is no good research on it for hair growth. It is gentle as a rinse or mist, but keep it in the fridge and make fresh batches every few days, as it spoils.

Who should avoid rosemary oil?

• People with sensitive skin or scalp conditions, such as eczema or psoriasis, without a doctor's advice.
• People who are pregnant or breastfeeding, who should check with a doctor before using essential oils.
• Anyone with a reaction: stop if you notice redness, burning or a rash.
• Children, unless a doctor says it is fine.

When to see a doctor

See a dermatologist if hair falls out suddenly or in patches, if you see scalp redness or scaling, or if thinning comes with tiredness or other symptoms. Iron deficiency, thyroid problems and hormonal changes such as perimenopause can all cause hair loss and need their own treatment.

Caring for thinning hair

• Be gentle: avoid tight styles and lower the heat; see heat damage and styling tools.
• Use volume tricks: a little dry shampoo at the roots adds lift.
• Try a fuller cut: soft layers or curtain bangs make hair look thicker.
• Choose dimensional color: see hair color ideas.

For castor oil, the other popular hair oil, see our castor oil guide.

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